Oswego Wastewater Treatment Plant Reduces Maintenance Liability
An Oswego, Illinois wastewater treatment plant, Fox Metro, has reduced its maintenance liabilities using variable frequency, ultimately providing greater system control and flexibility.
Fox Metro’s main pump building housed three constant pressure piston pumps. Sludge was being pumped over 1800 lateral feet through pipes, which were originally rated for 150 PSI, with actual pressure peaking around 100 PSI. The pumps could not maintain constant pressure, causing breaks in the shear pins of the piston pumps. They decided to replace one of the piston pumps with a rotary lobe pump connected to a 125 HP VLT 8000 AQUA variable frequency drive. The drive runs the motor based on feedback from a Danfoss pressure transmitter and pressure switch near the outfeed of the pump. This allowed a maintained optimal flow rate of 55 PSI. The drive can also slow or stop the pumps, preventing damage and maintenance needs.
In addition to reduced maintenance, the VLT 8000 series causes greater flexibility to the system as a whole, while also reducing the number of injuries to maintenance personnel because the new system does not require lubrication, which can cause the floors to be slippery.
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